Magnesium electrolyzer

ABSTRACT

THE PRESENT INVENTION RELATES TO MAGNESIUM ELECTROLYZERS HAVING CATHODES INTRODUCED THROUGH AN ELECTRICALLY INSULATING MATERIAL ON A LINING DEPOSITED ON AN ELECTROLYZER WALL.

' Dec. 4, 1973 v. P. sHEKA ETAL.

MAGNESIUM ELECTROLYZER Original Filed Dec. 16. 1970 2 Shoah-Sheet l N .QQ

Dec. 4, 1973 V. P. SHEKA ETAL MAGNESIUM ELECTROLYZER Original Filed Dec. 16. 1970 2 Shouts-Shoot 3 United sat-es Patent o Int. Cl. C22d 3/02, 3/08 U.S. Cl. 204-243 R 1 Claim ABSTRACT OF THE DISCLOSURE The present invention relates to magnesium electrolyzers having cathodes introduced through an electrically insulating material on a lining deposited on an electrolyzer wall.

This application is a continuation of application Ser. No. 98,544, led Dec. 16, 1970, and now abandoned.

The invention consists in that the electric insulating material with which the lining is coated is essentially synthetic magnesium alumina mica of the type of liuophlogopite.

Known in the art is a magnesium electrolyzer comprising cathodes introduced through a lining coated with an electric insulating material, anodes, cells for accumulation of magnesium and chlorine, and partitions separating said cells from one another.

To protect the lining against destruction caused by magnesium separated on the inner wall of the lining, through which the cathode is introduced, a conventional electrolyzer employs diabase plates.

Though the diabase plate possesses a substantial electrical resistance as compared to the material of the lining, the resistance is not sufficient to eliminate completely the electric current distribution on the plate and the cathode potential formed thereon, which results in separation on the diabase plate, of magnesium interacting With the oxides of the metals of the diabase plate and formation of compounds transforming into an electrolyte, thus leading to destruction of the plate and of the electrolyzer lining proper.

Besides, the diabase plates are rather brittle and are destroyed in the course of operation as they cannot resist impact loads.

The premature destruction of the diabase plate and subsequent destruction of the main material of the lining decreases the electrolyzer service time between general repairs.

It is an object of the present invention to provide such a magnesium electrolyzer in which a material for coating the lining would have less electrical conductivity.

Another object of the present invention is to provide such a magnesium electrolyzer in which a material for coating the lining would have less friability.

Still another object of the present invention is to provide such a magnesium electrolyzer which would have greater service time between general repairs.

These and other objects are accomplished by that in a magnesium electrolyzer comprising cathodes introduced through a lining coated lwith an electrical insulating ma- ICC terial, anodes, cells for accumulation of magnesium and chlorine and partitions separating said cells from one another, according to the invention, the electrical insulating material is essentially synthetic magnesium alumina mica of the type of fluophlogopite.

As a result of the present invention, there has been provided an electrolyzer whose lining is less liable to destruction at the point of introduction of the cathode, which increases the service time of the electrolyzer between its general repairs.

The following description of an exemplary embodiment of the present invention is given with reference to the accompanying drawings, in which:

FIG. 1 shows a longitudinal section of a magnesium electrolyzer built in accordance with the present invention;

IG. 2 is a section taken along line II--II of FIG. 1; an

FIG. 3 is a section taken along line III-III of FIG. 1.

A magnesium electrolyzer comprises a steel casing 1 FIGS. 1, 2 and 3) accommodating lining 2 made from a refractory material, steel cathodes 3 introduced through longigidinal wall 4 (FIGS. 2 and 3) of the lining 2, graphite anodes 5 (FIGS. 1, 2 and 3) introduced through holes provided in anode ceiling 6 (FIGS. l and 2), cells 7 (FIG. 1) for accumulation of chlorine, partitions 8 (FIGS. 1 and 2) made from a refractory material and secured in the longitudinal wall 4 through which the cathodes 3 are introduced, and in the lining wall 9 (FIGS. 2 and 3) opposite to said wall 4. The partitions 8 separate the cells 7 for accumulation of chlorine from cells 10 (FIG. 1) for accumulation of magnesium. The anode ceiling 6 of the cells 7 for accumulation of chlorine is tightly mounted on the partitions 8 and walls 4 and 9 of the lining, whereas extreme anode ceilings 11 are tightly mounted on the partitions 8, face walls 12 (FIGS. 1 and 3) and longitudinal walls 4 and 9 of the lining.

The cells 10 for accumulation of magnesium are closed from top with covers 13 resting upon the anode ceilings 6 and 11. The inner surface of the wall 4 through which the steel cathodes 3 are introduced, has plating 14 (FIGS. 2 and 3) made from a refractory electric insulating material-plates, synthetic magnesium alumina mica of the type of iluophlogopite of the formula KMg3[Si3AlO`10]F2 which is obtained by melting a charge of a stoichiometric composition corresponding to iluophlogopite.

With direct current passing through a molten electrolyte containing magnesium, sodium, potassium and calcium chlorides, chlorine is separated on the anode 5 and magnesium-on the cathode 3. Magnesium is not separated on the inner surface of the wall 4 through which the cathodes are introduced due to the fact that uophlogopite with which the wall 4 of the lining is coated possesses a rather high electric resistance (101e-101" ohm/ cm.). As a result of this, it does not conduct electric current and the plating made therefrom has no potential of the cathode contacting it.

Besides, uophlogopite possesses plastic properties and is less brittle than diabase and, consequently, is less liable to detruction caused by impact loads.

The above-mentioned properties of fluophlogopite make it possible to reliably protect -the lining made from the refractory material against destruction.

Due to this, as compared to conventional electrolyzers, a magnesium electrolyzer with a lining through which cathodes are introduced therein and which is coated with synthetic magnesium alumina mica of the type iluophlogopite, has a longer service time between general repairs owing to a low deterioration rate of the lining.

What iS Claimed is: I- i RueielenCesi', Cteld.fil l a y lt 1. In a magnesium electrolyzer of the type comprising: an electrolyzer bath provided with la lining; partitions UNITE D STATES PATENTS Y l 'Y forming cells in the electrolyzer for accumulation of chlo- 2,880,151 3/1959 Dean et al- 20470 rine and cells for accumulation of magnesium; anodes in 5 3,562,136 2/1971 Devafda et al 204-244 X the electrolyzer bath; cathodes introduced into the electro- 3,676,323 7/1972 Strelets et al 2MP-244 lyzer through said lining; and a layer of electrically insulating material deposited on said lining Where said cath- JOHN H' MACK Pnmary EFammr odes are introduced through the lining, the improvement D. R. VALENTINE, Assistant Examiner being in that said electrically insulating material is essen- 10 A Y tially synthetic magnesium alumina mica of the type of U.S. C1. X.R. luophlogopite. 204-70, 244, 245 

